Absolute myocardial mass difference and ventriculo–arterial coupling in morphologically defined left ventricular non-compaction: A multiparametric cardiovascular magnetic resonance study

Background Left ventricular non-compaction (LVNC) is increasingly recognized as a morphological phenotype rather than a distinct cardiomyopathy. Current cardiovascular magnetic resonance (CMR) criteria rely predominantly on static morphologic thresholds and may not adequately reflect dynamic myocardial adaptation. Purpose To investigate whether absolute myocardial mass difference (AD) represents a marker of structural–functional remodeling and to assess its relationship with hemodynamic and flow-related parameters in morphologically defined LVNC. Material and Methods In this retrospective study, 99 patients fulfilling Petersen and Grothoff CMR criteria for LVNC and 66 frequency-matched controls underwent multiparametric 1.5-T CMR. Volumetric indices, left atrial volume, cine-derived functional parameters, and aortic phase-contrast MRI flow timing indices, including time-to-peak velocity (TPV), ejection time (ET), and TPV/ET ratio, were analyzed. AD was defined as the indexed difference between end-diastolic myocardial mass and cycle-averaged myocardial mass. Between-group comparisons, effect size analysis, correlation testing, and ROC analysis were performed. Results AD was significantly higher in LVNC patients than in controls (3.71 ± 2.43 vs. 2.03 ± 1.49 g/m 2 ; P < 0.001) and demonstrated a large effect size (Cohen's d = 0.81). LVNC patients exhibited increased end-diastolic and end-systolic volume indices (both P < 0.001), preserved cardiac index, and altered systolic flow timing characteristics. AD correlated positively with left atrial volume ( r = 0.39; P < 0.001) and cardiac index ( r = 0.27; P = 0.007), whereas no significant association was observed with TPV/ET. ROC analysis demonstrated modest discriminatory performance (AUC = 0.71). Conclusion In morphologically defined LVNC, AD is increased and associated with atrial remodeling and preserved hemodynamic adaptation. These findings suggest that AD may represent a marker of dynamic structural–functional remodeling rather than static trabecular excess. Incorporation of AD into multiparametric CMR assessment may improve phenotypic characterization and help distinguish compensated hypertrabecularization from clinically relevant myocardial disease.